What a great threesome these stones make. They are not actually an alignment (or maybe they are) but they sit quite unassumingly in a triangular island at a fork in the road.
There are some stories to how these ended up here that I will add later.
Head south from Drogheda along the R108 and take the fourth left about (6km) after where the R150 crosses. Continue for about 1.8km and you will reach these stones.
These stones were alledgedly thrown from Tara by Finn MacCool (Fionn MacCumhaill) and are known locally as The Jack Stones.
This is an explanation of (and a bit of a disclaimer for) the coordinates I provide.
Where a GPS figure is given this is the master for all other coordinates. According to my Garmin these are quite accurate.
Where there is no GPS figure the 6 figure grid reference is master for the others. This may not be very accurate as it could have come from the OS maps and could have been read by eye. Consequently, all other cordinates are going to have inaccuracies.
The calculation of Longitude and Latitude uses an algorithm that is not 100% accurate. The long/lat figures are used as a basis for calculating the UTM & ITM coordinates. Consequently, UTM & ITM coordinates are slightly out.
UTM is a global coordinate system - Universal Transverse Mercator - that is at the core of the GPS system.
ITM is the new coordinate system - Irish Transverse Mercator - that is more accurate and more GPS friendly than the Irish Grid Reference system. This will be used on the next generation of Irish OS maps.